If \(\mbox{$(x_{n})_{n \in \mathbb {N}}$}\)  is a bounded sequence of points of \(X\) , then for \(\mbox{$A_{n}$}=\lbrace \mbox{$x_{k}$}: k \ge n \rbrace \) , and \(\mbox{$\mathcal {A}$}= \lbrace \mbox{$A_{n}$}: n \in \mbox{$\mathbb {N}$}\rbrace \) , \(c(\mbox{$(x_{n})_{n \in \mathbb {N}}$}):=c(\mbox{$\mathcal {A}$})\) ,
\(r(\mbox{$(x_{n})_{n \in \mathbb {N}}$}):=r(\mbox{$\mathcal {A}$})\)  are, respectively, the (asymptotic) centre, and the (asymptotic)
radius of \(\mbox{$(x_{n})_{n \in \mathbb {N}}$}\)  (see [1]}).
